It is common to use an image discharge or fadeout lamp to control development of a xerographic photoconductor member with a minimum use of developer material by energizing the lamp at preset periods. The lamp which is energized at preset periods during the copying cycle serves to dissipate the charge in selected areas of the photoconductor member normally between images to prevent development thereof. This in turn reduces the use or consumption of developer material as well as the load on the photoconductor member cleaning apparatus to effect increased efficiency of high speed machines which use a great deal of developer material.
It is further known that the timing of the lamp on and off cycles may be varied for different operating modes in the case of image reductions to effect a greater on period of the lamp for a predetermined image reduction as described in U.S. Pat. No. 3,860,338 which is commonly assigned with the instant application. The instant application is for an improvement to the control of the lamp which enables copying document material greater in length than an 81/2 inch document which is the reference used to control the turn on of the lamp in the pitch direction. Thus, by the instant invention the turn-on period of the lamp is delayed by a preset period during the pitch distance between image frames on the photoconductive member to enable the copying of standard length 81/2 inch documents during a normal mode of operation and lengths greater than standard length during a special mode of operation. Thus, in a special mode documents having tabs or 9 inch documents could be copied.